( ii ) 



colour. The larva, which is equally large and as well illu- 

 minated as the adult insect, may be recognised by its darker 

 colour and the presence of but a single claw on each foot. 



If the luminosity of the adult serves for sexual attraction, 

 it must have some totally different object in the larva. We 

 have to fall back upon the theory of warning colours, to meet 

 this case. But the question occurs : Why should an insect 

 that travels only in the dark require to draw attention to its 

 unpalatability ? The same problem occurs in the case of the 

 winged male, which does not require to advertise its presence 

 when seeking the apterous female. I have repeatedly ob- 

 served, in fact, that the male shuts off its light when approach- 

 ing a " calling " female. 



Mr. DoNiSTHORPE observed that both the eggs and larvae 

 of the English glow-worm are luminous. 



An Ingenious Device. — Dr. H. Eltringham exhibited an 

 instrument made to his instructions by the Cambridge Scien- 

 tific Instrument Company, for cutting paraffin blocks perfectly 

 square preparatory to placing them on the microtome. He 

 remarked on the difficulty usually experienced in cutting these 

 blocks and the impossibility of obtaining good section ribbons 

 if the paraffin containing the object were not cut perfectly 

 square. The instrument consisted of a carrier for the block- 

 holder sliding in an inclined groove of V section, and on the 

 opposite end of the bed-plate a pair of level guides on which 

 to slide the knife. The carrier had on it a square plate at right 

 angles to its long axis and arranged to slide in the V groove. 

 The inclination of the groove gave adjustment for height, 

 whilst the square plate on the carrier brought the latter, and 

 consequently the paraffin block, into four possible positions, 

 each corresponding to one side of a square, in relation to the 

 travel of the knife. With this instrument a paraffin block 

 could be cut square with absolute precision and of any size in a 

 few seconds. 



The Life-history of Agrotis lucernea. — Mr. Lupton 

 communicated the following notes : — 



I\Ir. Joseph Walker of Torquay has investigated the life- 

 history of this moth, and, as it differs very materially from that 

 set out by most of our authorities, he has asked me to com- 



